Lock-stitch shoe sewing machine



July 14, 1931. o. LAWSON Locx STITCH SHOE [SEWING MACHINE Filed une 12, 1926 2 Sheets-Sheet 1 A i i illlLi fFnwLlLL T v. a I N E v N I 0. L. LAWSON LOCK STITCH SHOE SEWING MACHINE July 14, 1931.

Filed June 12, 1926 2 Sheets-Shem 2 1 1 III! Patented July 14, 1931 uNrr sosrATE-s PATENT OFFICE OSCAR L. LAWSON, OF LYNN, MASSACHUSETTS, ASSTGNOR, BY MESNE ASSIGNMENTS,

TO UNITEDSI-IOE MACHINERY CORPORATION, OF IPATERSON, NEW JERSEY, A COR.-

PORATION. OF NEW JERSEY LOCK-STITCH SHOE Application filed June 12,

This invention relates to lock-stitch shoe sewing machines of the general type shown and described in Letters Patent to J. H.

i Reed, No. 1,688,056, granted October 16,

1o threadat theupper side of the work, while at the under-side of the work is a work supporting horn provided with a looper or whirl which supplies a cop or needle thread, together with takeup and stitch setting mechanism to, draw the needle loop over the shuttle andset thestitch. The present invention has to do particularly with theinst'rumentalities at the upper side of the work and has for its general object certain improvements in this part of the mechanism which will permit the machine to be operated at a higher speed than has heretofore been possible with' machines of this type. I The moreparticular objects of the invention, together-with means whereby the latter may be carried into effect, will best be understood from the following description of a preferred embodiment thereof illustrated in the accompanying drawings. It will "be understood, however, that the particularconstruction described andshown has been chosen for illustrative purposes merely, and that said invention, as "defined byrthe 35 claims hereunto appended, maybe otherwise embodied without departure from the spirit and scope thereof.

In said drawings: L I Fig. 1 is a side elevation of the upper part of the machine.

Fig. 2 is an enlarged front elevation, partly broken away. I r

Fig. 3 is a horizontal section taken substantially on the line 33,'Fig. 2.

Fig. 4; is'an enlarged side elevation of a portion of the mechanism shown' in Fig. 1, looking from theopposite side of the ma chine.

Fig. 5 is a further enlarged front elevation of the stitch-forming instrumentalities' SEWING MACHINE 1926. Serial No. 115,457.

shown in Fig. 2, showing the parts in a different position.

Fig. 6 is a section taken substantially on a line 66, Fig. 5.

In the embodiment of the invention here in shown, the head frame is carried by a standard 16 which rises from a suitable base (not shown) on which is mounted a horn 17 for supporting the work A. The needle 18, which is above the work, is straight and is formed adjacent its pointed lower end with an open loop-engaging hook 19, said needle beingcarried by a needle bar 20 guided for rectilinear reciprocating movement in the head 15. Within the tip of the horn 17 and therefore below the work or at the opposite side thereof from the needle 18, is a whirl 21 which is rotatably mounted in said horn and isprovided with an eccentric opening through which the cop. or needle thread G passes and with an axial opening to receive the point of the needle when the latter descends to penetrate the work, whereby said whirl operates to form a loop about the needle immediately above the hook of the latter. Thereafter, as the needle rises, the loop so formed is drawn upwardly through the work. Above the work, or at the same side thereof as the needle, is an oscillating discoidal shuttle 22 carrying a shuttle thread S and rotatably mounted in a shuttle race suitably supported at the under side of the head '15 and preferably formed with a hinged side 23 to facilitate the insertion and removal of the shuttle. The shuttle22 is provided with a hook or beak 24 adapted, when the needle rises, to receive the loop of needle thread from the needle hook and pass it about the shuttle and shuttle thread. The machine also includes, below the work, suitable takeup mechanism (not shown) acting on the needle thread C to draw the needle loop from the shuttle and down upon the work, thereby completing the formation of the stitch. During the formation of each stitch the work is clamped upon the horn 17 by a presser foot 25, and between the formation of successive stitches said work is fed along the line of the seam by means of a combined feed point and awl 26 which serves to perforate or incise the work to facilitate the passage of the needle therethrough. The presser foot is carried by a presser foot bar 27 which is normally pressed downwardly by a spring 28 and is periodically raised between the formation of successive stitches to permit feeding the work by means of a bell crank lever 29. The presser foot 25 may also be manually raised to permit removal and insertion of the work bya lever 30 engaging the presser foot bar 27 and connected by a link 31 with a second lever 32 connected by a link 33 with a suitabletreadle (not shown) at the base of the machine. The feed point 26 is carried by a slide t'which is vertically movable in a second slide 35 guided for horizontal movement in a bracket 36 depending from the lower side of the head frame 15. The slides 34 and 35 are'actuated by mechanism generally indicated at 37 to cause the feed point 26 to move from the position shown in full lines in Fig. 2 downwardly into engagement with the work to incise the latter, thence forwardly into a position in the path of movement ofthe needle 18 as shown in dotted lines in Fig. 2 to feed the work, and thence upwardly and izearwardly into its starting position. The mechanism for producing the foregoing movements of the feed point as herein shown is of the type shown in Letters Patent to J. H. Reed, No. 1,706,743, granted hlarch 26, 1929, although for the purposes of the pres;

'ent invention any suitable type of feed mechanism may be employed'for this purpose. The several instrumentalities above the work are actuated from a horizontally disposed main or power shaft 38 journalled in the head 15, while the instrumentalities below the work are actuated'throu'gh suitable connections (not shown): from a vertical shaft 89 extending downwardly through the standard 16 and operatively connected with the shaft 38 by suitable gearing 40. The shaft 38' receives power from any suitable source through pulley 4-1 loosely mounted thereon and connected therewith by means of a clutch "l2 operated through suitable connections indicated at 43 by a treadle' (not shown) at the base of the machine.

In machines of the type above outlined, as heretofore constructed, it has been. necessary to operate the stitch-forming instrumentalit-ies, and particularly the needle and shuttle, alternately and intermittently and in the proper sequence in order to-permit them properly to perform their several functions. Thus, the usual cycle of operations has included, first, a complete reciprocation of the needle from its uppermost position downwardly through the work to receive a loop from the whirl 21 and thence upwardly to a starting point to draw the loop through the work, followed by an oscillation of the shuttle to cause its beak to take the loop from the needle and pass it about the shuttle and then return to its starting point. Since, in order to permit the shuttle beak to take the needle loop from the needle, the path of movement of the shuttle beak must cross the path of movement of the needle, it has heretofore been necessary, in order to avoid interference of the shuttle beak and needle with each other, that the shuttle remain stationary during the reciprocation of the needle, and that the needle remain stationary during the oscillation of the shuttle. This necessity of operating the needle and shuttle successively, each during a separate part of the cycle of operations, has heretofore definitely limited the speed of operation of machines of this. type. Moreover, the are through which the shuttle can: be oscillated has been limited by the time avail:- able for this operation, so that difficulty has been encountered in the failure of the loop to be properly cast about. the shuttle whenever any attempt has been made to speed up the machine.

In accordance with the present invention, the path of movement of the shuttle hook is offset from the path. of movement of the needle,and separate means provided for transferring the-needle loop from the needle hook to the shuttle beak, said. means being also operative to spread said loop andcarry oneleg' thereof. to the rear of the shuttle, thereby positively insuring the passage of the loop about the shuttle. Since the needle and shuttle beakv move' inv different paths, the needle and shuttle may be operated in proper relation coincidentally instead ofsuccessively and-alternately, thereby permitting the reciprocation of the needle and the oscillation: of the shuttleeach to'be spread over a considerable portion of the cycle of operations of the machine, instead of requiring the'operation of eachto be limited to av relatively small fractionof: said cycle. Furthermore, the shuttle may be reciprocated through substantiallya complete circle (said shuttle being preferably oscillated through an arcofapproximately 350), thereby further insuring the proper casting of the needle loop; over the-shuttle.

In the construction shown, the shuttle; 22 is oscillated about a fixed longitudinalv axis by means of a shuttle shaft Meprovided with a finger 46 which engages a notch in the periphery of the shuttle; The shuttle shaft l4 carries an elongated pinion! 47 which meshes with a segmental rack 48'carried by a lever 49 pivoted intermediate its endsto the head 15 and carrying at its upper end. a

cam roller 50 cooperating with a cam 51 a on the main shaft 238i The. form of the cam 51 is such as to cause the shuttle to be: oscillated through approximately a complete circle (preferably through about 350); and

to distribute this oscillation: over the greater portion of the cycle of operations, as above described. The needle bar 20 is actuated by a cam lever 52 pivoted at one end to the head frame 15 and connected at its opposite end by a link 53 with the needle bar 20, said lever carrying intermediate its ends a cam roller 54 working in a groove in a cam 55 on the main shaft 38. The form of the cam 55 is also such as to cause the needle bar to be reciprocated substantially continuouslv. each complete reciprocation of the needle bar taking place substantially coincidentally with an oscillation of the shuttle.

Connected by a short" link 56 with a fixed stud 57 on the under side of the head (see particularly Fig. 3) is a carrier 59 to one end of which is secured a loop spreader 58 having an offset wedge-shaped end. Secured to the other end of the carrier 59 is one end of an adjustable link 60 the opposite end of which is pivoted between ears 61 formed by the bifurcated end of a stud 62 carried by the free end of an arm 63 on a rock shaft 6tjournalled in bearings 65 on the head frame 15. The rock-shaft 64 is provided with a. second arm 66 which carries a cam roller 67 working in a groove in a cam 68 on the main shaft 38.

The arrangement of parts is such as to cause the point of the loop spreader 58 to swing periodically across the path of move ment of the needle 18 in a plane substantially perpendicular to the needle and on an are substantially tangential to the seam. It will be seen that this path of movement of the loop spreader has a component in the direction to cause said loop spreader to enter the needle loop, and a. component transverse to said direction. The latter component, together with the wedge-shaped form of the loop spreader, causes said loop spreader to open the loop and carry the rear leg thereof rearwardly toward the shuttle.

In operation, the needle 18 rises above the work carrying with it the loop of copy thread C, shown in Fig. 2, and the loop spreader '58 moves forwardly or toward the left in Figs. 2, 3, 5 and 6, causing the point thereof to enter said loop. At this time the shuttle 22 commences to turn in a counterclockwise direction, causing the beak 24 to pass over the loop spreader 58, the shape and path of movement of which are such as to carry the rear leg of the loop across the path of movement of said beak, so that the latter passes through the loop. The needle now starts dovmwardly, causing its hook to release the loop, and as the counterclockwise rotation of the shuttle continues, the loop is carried over the shuttle which, to gether with the shuttle thread S, is thereby passed through said loop. The width of the loop spreader, combined with the rearward component of its movement, are suflicient to carry the rear leg of the loop entirely'to the rear of the shuttle,as shown in Fig.6, thereby preventing sticking of the thread on the shuttle and insuring its passage thereover. Since the shuttle is turned through approximately a complete circle, the sheddingof the loop by the shuttle is also insured.

As above stated, the needle is reciprocated substantially continuously in the sense that its cycle of operations is distributed over substantially-the entire cycle of operations of the machine, although it may be desirable, in some instances, to provide a slight dwell when the needle reaches the lower limit of its movement in order to insure the proper formation of the loo-p therearound by the whirl, and also to permit said needle to pause momentarily in its descent while the loop is being cast over the top of the shuttle in order to avoid any danger of fouling the thread. These, however, are matters of choice and, if the mechanism be suitably designed, may be necessary.

Having thus described my invention, I claim:

1. In a lock-stitch shoe sewing machine, in combination, a hooked needle, means for reciprocating said needle to cause the same to penetrate the work and be withdrawn therefrom, means for forming a loop of thread about the needle hook when said needle has penetrated the work, a shuttle having a beak to receive the needle loop when said needle is withdrawn from the work, a loop spreader, a carrier for said loop spreader, a link mounted at one end to swing about a fixed pivot and connected at its opposite end to said carrier, and means for reciprocating said carrier.

2.. In a lock-stitch shoe sewing machine,

in combination, an oscillatory discoidal shuttle, a straight hooked needle associated therewith arranged to operate opposite substantially the center portion of the face of the shuttle, and a wedge shaped loop spreader disposed in a plane substantially perpendicular to the needle and adapted to carry one leg of the needle loop well to the rear of the shuttle during the loop taking movement of the shuttle.

3. In a lock-stitch shoe sewing machine,

in combination, an oscillatory discoidal shuttle, a' straight hooked needle associated therewith arranged to operate opposite substantially the center portion of the face of the shuttle, and a wedge shaped loop spreader operable in a plane perpendicular to the needle and in a direction substantially op posed tothe direction of the loop taking stroke of the shuttle to carry one leg of the a straight hooked needle arrangedt'o operate opposite substantially the center portion of the face of the shuttle, a wedge shaped 100p spreader disposed in aplane perpendicular to: the needle, and means for actuating the loop spreader in a direction opposed to the direction of the loop taking stroke of the shuttle to carry one leg oi the needle 100p Well to the rear of the shuttle.

OSCAR L LAWSON. 

